1. Field of the Invention
The invention relates to a detecting circuit, and more particularly to a clock detecting circuit.
2. Description of the Related Art
Nowadays, brushless DC motors are widely used. A typical problem with a controller of a conventional brushless DC motor is that clock precision of a microprocessor thereof is not high enough, which affects normal control and operation efficiency thereof, increases power consumption, or even leads to a destruction of the controller and the motor.
To solve the above-mentioned problems, several methods are employed: clock circuits with high precision are used, and special watchdog chips are used to detect clock precision of the microprocessors. However, these methods have several disadvantages: firstly, structure of the circuit using the methods is complex, secondly, production cost thereof is very high, and thus application of the brushless DC motor is limited.